In the prior art, a semiconductor analog multiplier circuit includes a series aiding string of diodes, each diode conducting an input current from one of plural sources and producing a junction voltage proportional to a logarithm of the current conducted therethrough. A pair of opposite conductivity type transistors convert the voltage across the string of diodes into an output current having a magnitude related to the magnitudes of the input currents. For producing an output current which has a magnitude proportional to the product of the magnitudes of the input currents, it is necessary to use diodes having an exponential coefficient equal to twice the exponential coefficient of the base-emitter junctions of the transistors.
A problem arises when the prior art multiplier circuit is fabricated as a monolithic integrated circuit. In such a circuit, the exponential coefficient of the diodes essentially equals the exponential coefficient of the base-emitter junctions of the transistors. With the exponential coefficients of the diodes and transistors being equal, the output current of the prior art multiplier circuit is proportional to the square root of the product of the input currents rather than being proportional to the product of the input currents as desired.